poisoning

food poisoning

Acute gastrointestinal illness from eating foods containing toxins. These toxins may be poisons that occur naturally in plants and animals, chemical contaminants, or toxic products of microorganisms. Most cases are due to bacteria (including salmonella and staphylococcus) and their toxins (including botulism). Some strains of E. coli can cause severe illness. Chemical poisons include heavy metals (seemercury poisoning), either from food or leached out from cookware by acidic foods. Food additives may have a long-term cumulative toxic effect. Seealsofish poisoning; mushroom poisoning.

Sometimes fatal effect of eating any of the 70–80 species of poisonous mushrooms, or toadstools. Many contain toxic alkaloids. The most deadly, Amanita phalloides (“death cup”), causes violent abdominal pain, vomiting, and bloody diarrhea. Severe liver, kidney, and central-nervous-system damage lead to coma. Over half the victims die. Treatment with thioctic acid, glucose, and penicillin or by filtering the blood with charcoal may be effective. A. muscaria causes vomiting, diarrhea, excessive perspiration, and confusion, with recovery within 24 hours. Gyromitra esculenta toxin is usually destroyed by cooking, but in susceptible people it affects the central nervous system and breaks down blood cells, causing jaundice. Some poisonous mushrooms resemble harmless ones, so extreme caution is needed in wild-mushroom gathering.

Harmful effects of drugs, from overdose or sensitivity to regular doses. Many medicines are dangerous; the margin between dose and overdose is often narrow. A normally safe dose may be toxic in some people, over time, or in combination with certain foods, alcohol, or other drugs. Safeguards to prevent drug poisoning include testing in animals, then human volunteers, and then patients. Drugs unsafe for self-medication are available only to doctors or by prescription. Pharmacists advise the public on proper use.

Poisoning by accumulation of lead in the body. Large doses cause gastroenteritis in adults and brain disorders in children. Anemia, constipation and abdominal spasm, confusion, a progressive paralysis, and sometimes brain cancer result from chronic exposure. Children are particularly susceptible to nerve and brain damage; sensitive tests show that even low levels of lead can harm children and are linked to behavioral problems. Sources in the home include lead-based paint, lead drinking-water pipes, and lead-glazed tableware. Babies, who put things in their mouths, are at highest risk. Working where lead is used and exposure to some insecticides are other risk factors. The U.S. phaseout of lead in gasoline was completed in 1996; similar bans are being implemented worldwide. Treatment involves giving antidotes that bind (seechelate) the lead in the tissues.

Invasion of the bloodstream, after surgery or infectious disease, by microorganisms—typically gram-negative (seegram stain) bacteria—and the toxins they release. The latter trigger immune responses and widespread coagulation in blood vessels. High fever, chills, weakness, and sweating are followed by a drop in blood pressure. Multiple infections are often present, requiring broad-spectrum antibiotics as well as drainage of foci of infection. Without immediate treatment, septic shock follows, with a mortality rate over 50percnt. Invasive technology and antibiotic-resistant bacteria in hospitals have made septicemia more severe and more common. Seealsobacteremia.